Enhanced DNA damages of human prostate cancer cells induced by radiofrequency capacitive hyperthermia pre- and post X-rays: 6 MV versus 15 MV

Objective: This study aimed to determine the effect of 13.56 MHz radiofrequency [RF] capacitive hyperthermia [HT] on radiosensivity of human prostate cancer cells pre and post X-ray radiation treatment [RT]

Materials and Methods: In this experimental study, the human prostate cancer cell line DU145 was cultured as 300 micro m diameter spheroids. We divided the spheroids into group I: control, group II: HT at 43[degree]C for 30 minutes [HT], group III: 4 Gy irradiation with 6 MV X-ray [RT [6 MV]], group IV: 4 Gy irradiation with 15 MV X-ray [RT [15 MV]], group V: HT+RT [6 MV], group VI: HT+RT [15 MV], group VII: RT [6 MV]+HT, and group VIII: RT [15 MV]+HT. The alkaline comet assay was used to assess DNA damages in terms of tail moment [TM]. Thermal enhancement factor [TEF] was obtained for the different treatment combinations

Results: Mean TM increased with increasing photon energy. Group II had significantly greater TM compared to group I. Groups III and IV also had significantly higher TM compared to group I. Significant differences in TM existed between groups V, VII, and III [P<0.05]. We observed significant differences in TM between groups VI, VIII, and IV. TEF values demonstrated that enhanced response to radiation was more pronounced in group V compared to the other combined treatments

Conclusion: Our results suggest that HT applied before RT leads to higher radiosensivity compared to after RT. HT at 43[degree]C for 30 minutes added to 6 MV X-ray causes higher enhancement of radiation compared to 15 MV X-ray

role of radiofrequency hyperthermia in the radiosensitization of a human prostate cancer cell line

Objective: This study evaluated enhanced induced DNA damages and apoptosis of a spheroid culture of DU145 prostate cancer cells treated by a combination of radiofrequency hyperthermia [RF HT] with radiation treatment [RT] from an external radiotherapy machine compared to RT alone

Materials and Methods: In this experimental study, DU145 cells were cultured as spheroids until they reached 300 micro m in diameter. We exposed these cultures to either: RF HT for 90 minutes at 43[degree]C originated from a Celsius TCS system, RF HT followed by RT at doses of 2 Gy or 4 Gy [15 MV energy] with 15-minute interval, or RT alone at the above mentioned doses. The trypan blue exclusion assay, alkaline comet assay, and annexin V/PI flow cytometry were performed to measure cell viability, the amount of DNA damage in an individual cell as the tail moment, and percentage of induced cell apoptosis in response to treatments explained

Results: We calculated the thermal enhancement factor [TEF] for the combined treatment regime. RF HT followed by the 4 Gy dose of RT resulted in minimum viability [85.33 +/- 1.30%], the highest tail moment [1.98 +/- 0.18], and highest percentage of apoptotic cells [64.48 +/- 3.40%] compared to the other treatments. The results of the TEF assay were 2.54 from the comet assay and 2.33 according to flow cytometry

Conclusion: The present data suggest that combined treatment of mega voltage X-rays and RF HT can result in significant radiosensitization of prostate cancer cells

novel phantom design for brachytherapy quality assurance

Background: One major challenge in brachytherapy is to verify the accuracy of dose distributions calculated by the treatment planning system. In this project, a new phantom design has been introduced for quality assurance of dose distributions in gynocological [GYN] brachytherapy implants using EBT GafChromic film. Materials and Methods: This phantom has been designed and fabricated from 90 slabs of 18×16×0.2 cm[3] Perspex to accommodate a tandem and ovoids assembly, which is normally used for GYN brachytherapy treatment. In addition, this phantom design is allowing the use EBT GafChromic films for dosimetric verification of GYN implants with Cs-137 Selectron LDR system. With this assembly, GafChromic films were exposed using a plan designed to deliver 2.5 Gy dose to point "A" in Manchester system for tandem and ovoids configurations and to deliver 1.5 Gy of dose to 0.5 cm distance from the lateral surface of ovoids for using ovoid-pair. The measured dose distributions with GafChromic films were compared with the TPS isodose lines both numerically and spatially. For a quantitative analysis of the results, the measured doses values at several points of interest were evaluated with the treatment planning data and values obtained following the TG-43 dose calculation formalism. Results: The results of these investigations have indicated that the new phantom design enables us to measure differences of greater than +/-6% for LDR brachytherapy GYN treatments. Conclusion: The new phantom design could be utilized for the QA procedure of the brachytherapy remote after loading systems to confirm the accuracy of dose distribution in GYN implants

Local hyperthermia case study

Background: prostate cancer is the second most common reason of death in men. Multidisciplinary therapy is the best treatment option, although, there is no common consent on optimal therapy for advanced prostate cancer

Case Presentation: the present study reports a case of 75 year-old man who had a huge heterogeneous soft tissue mass lesion with non-homogeneous enhancement consisted low attenuated foci occupying pelvis cavity and lower abdomen with loss of mesenteric fat and invasion to posterior bladder wall due to T4N1Mx prostate cancer. The patient was treated with adjuvant radiotherapy [RT] plus local hyperthermia [HT]

Conclusion: this report shows the potential capability of HT application during RT. Radiotherapy with hyperthermia combination revealed a dramatic response in this case and after treatment it left the patient asymptomatic

High-dose-rate 192Ir brachytherapy dose verification: a phantom study

The high-dose-rate [HDR] brachytherapy might be an effective tool for palliation of dysphagia. Because of some concerns about adverse effects due to absorbed radiation dose, it is important to estimate absorbed dose in risky organs during this treatment. This study aimed to measure the absorbed dose in the parotid, thyroid, and submandibular gland, eye, trachea, spinal cord, and manubrium of sternum in brachytherapy in an anthropomorphic phantom. To measure radiation dose, eye, parotid, thyroid, and submandibular gland, spine, and sternum, an anthropomorphic phantom was considered with applicators to set thermoluminescence dosimeters [TLDs]. A specific target volume of about 23 cm3 in the upper thoracic esophagus was considered as target, and phantom planned computed tomography [CT] for HDR brachytherapy, then with a micro-Selectron HDR [192Ir] remote after-loading unit. Absorbed doses were measured with calibrated TLDs and were expressed in centi-Gray [cGy]. In regions far from target [>/= 16 cm] such as submandibular, parotid and thyroid glands, mean measured dose ranged from 1.65 to 5.5 cGy. In closer regions [

Dosimetry of Esophageal radiotherapy: a phantom study

Esophageal cancer is the eighth most ordinary cancer and the sixth most common cancer between the males and ninth for females in the world; its major and effective treatment is external radiotherapy. This type of cancer can be found in different areas of esophagus including cervical, upper, middle and lower esophagus. In this treatment, healthy tissues such as the trachea, spine and sternum and even thyroid receive dose and it is important that the absorbed doses by these organs be in their tolerance dose levels. We measured the surface and depth doses in an anthropomorphic phantom using thermoluminescent dosimeters. To do so, a target volume was considered in the phantom as a primary esophageal tumor with margins of 5 cm in the distal and proximal, and 3 cm in lateral. Phantom was CT planned and treatment was performed according to patient treatment. The considered measurement locations were Eye, right and left Parotid, left and right Submandibular, left and right Thyroid, Trachea, Manubrium of Sternum and Spine. Our results show that in places located further to primary beam such as Thyroid [phase one], Trachea, Spine and Sternum, the difference between dose from TPS and TLD measurements is observed. In organs which have placed within scattered radiation, the difference is insignificant [P-value>/=0.05], although some differences might cause by TLD limitations. In conclusion, the TPS calculated and TL measured doses distinguish significantly at the spine [depth], trachea [depth] and manubrium of sternum especially in phase 1 which might be due to the calculation algorithm used by the planning system which is reliable in homogeneous medium, but TL measurements were performed in the heterogeneous anthropomorphic phantom

[Evaluation of diagnostic reference dose levels in ct-scan examinations of adolescence in Tehran: a brief report]

Today, a CT scan examination play an important role in disease diagnosis and thus allocates a significant dose of medical X-ray examinations. One of the important principles in the use of ionizing radiations is to observe radiation protection principles. Evaluating patient's absorbed dose and implementing the strategies for reducing dose are prior in safety issues. To achieve this purpose, sufficient studies should be performed in this regard. Therefore, patient's absorbed dose and the factors affecting have been studied in this research. This study aims to present and develop an acceptable level of absorbed dose in CT scan examinations. Diagnostic reference dose level in the adult age group [older than 15 years] has been studied in eleven CT scan centers in Tehran. For this purpose, CT scan examinations prevalent in above-mentioned centers were chosen and Weighted Computed Tomography dose index [CTDIw] and dose length product [DLP] parameters were studied. Standard phantoms with 16 and 32 diameters of Polymethylmethacrylate [PMMA] origin have been used in the centers for CT scan calibration process. CTDIw third quartile has been considered as the diagnostic reference dose level [DRL]. Rate of diagnostic reference dose in the adult age group [older than 15 years] for the head, sinus, lungs, abdomen and pelvis are 50.87, 38.27, 8.05 and 9.11 mg, respectively. Dose measurements made in this survey have been used to set up local DRLs and can be used as a template for national DRLs. Value of diagnostic reference dose for the head examinations is more than the other parts and diagnostic reference dose in Tehran city in the Adult age group and the protocols compared is less than national reference dose.

Evaluation of the combined effect of 2ME2 and 60Co on the inducement of DNA damage by IUdR in a spheroid model of the U87MG glioblastoma cancer cell line using alkaline comet assay

In this study, we investigated the combined effect of 2-Methoxyestradiol [2ME2] and 60Co on the cytogenetic damage of iododeoxyuridine [IUdR] in the spheroid model of U87MG glioblastoma cancer cell lines by alkaline comet assay. U87MG cells were cultured as spheroids with diameters of 350 micro m. As control, the spheroids of one plate were not treated. Other cultures were pretreated with 2ME2 [250 micro M] for one volume doubling time [1 VDT]. After this time, the subsequent treatments were performed according to the following groups: 1. Vehicle [this sample was not treated in the 2nd VDT] 2. Treated with 2ME2 [250 micro M] for 1 VDT 3. Treated simultaneously with 2ME2 [250 micro M] and IUdR [1 micro M] for 1 VDT 4. Treated with 2ME2 [250 micro M] for 1 VDT then irradiated with 60Co [2 Gy] 5. Treated simultaneously with 2ME2 [250 micro M] and IUdR [1 micro M] for 1 VDT then irradiated with 60Co [2 Gy] Then the DNA damage was evaluated using the alkaline comet assay method. The results showed that 2ME2 in combination with gamma irradiation of 60Co significantly [p<0.001] increased the DNA damage by IUdR as compared to the control group. Thus the combination of these two agents increased the cytogenetic effects of IUdR in the spheroid culture model of U87MG glioblastoma cell lines. By inhibiting the HIF-1 protein and preventing the G0 phase arrest, 2ME2 causes an increased progression into S phase and increases the IUdR absorption. Then the DNA damage in the spheroid cells increases as the uptake of IUdR is increased. These results suggest that the combined use of 2ME2 and 60Co can increase the radiosensitization effect of IUdR

effect of ethanolic extract of propolis on radiation-induced mucositis in rats

To assess the efficacy of ethanolic extract of propolis in radiation-induced mucositis in rats. This study was performed in the Dental Faculty, Shahid Rajaee Hospital of Babol University of Medical Sciences, Babol, Mazandaran, Iran from August 2008 to September 2009, It was carried out on 21 male Wistar rats, age 7-11 weeks, and weighing 160 +/- 20g. They were divided into 3 groups. Group A received intraperitoneal [ip] injections of 100 mg/kg ethanolic extract of propolis [EEP], group B received ip injections of 200 mg/kg EEP, and the control group [group C] received 10% ethanol [10ml/kg [ip]] just before x-ray irradiation. All rats were irradiated in the head and neck region by an x-ray device at a dose rate of 15 gray [Gy] for 9 minutes and 39 seconds. The daily injection continued for the next 10 days, and the lips and tongues of the rats were examined daily to assess the intensity of lesions induced by irradiation. In group C, the first signs of ulcers appeared on the first day, while they appeared on the fourth day in group B, and third day in group A. The severity of ulcers was greatest in group C, and least in group B. Propolis is effective in reducing and delaying radiation-induced mucositis in an animal model, however, further study and evaluation is required